docs: def run_job(key, node):
      """Run a job. This applies the function node, and returns a |ResultMessage|
      when complete. If an exception is raised in the job, the |ResultMessage|
      will have ``'error'`` status.
  
      .. |run_job| replace:: :py:func:`run_job`"""
      try:
          result = node.apply()
          return ResultMessage(key, 'done', result, None)
  
      except Exception as exc:
          return ResultMessage(key, 'error', None, exc)